Rapid Maxillary Expansion Appliance Research Articles

Evaluation of the Effects of Orthopedic Treatment on the Dentofacial Structure and Upper Airway of Subjects with Skeletal Class III Malocclusion.

The present study aimed to evaluate the effect of rapid maxillary expansion (RME) and face mask treatment on the upper airway in patients with maxillary retrusion in two dimensions using digital cephalograms and volumetric evaluation using acoustic rhinometric measurements. A total of 22 individuals with a concave profile and skeletal and dental Class III malocclusion during growth and development with a mean age of 9.9±1.38 years were included in the study. A bonded RME appliance and a petit face mask were adapted for the patients. Before treatment (T0) and after maxillary protraction (T1), lateral cephalometric films and acoustic rhinometric recordings were obtained. The dependent sample t-test was used for statistical evaluation. Cephalometric analysis revealed forward movement of the maxilla and backward downward rotation of the mandible. A significant increase was observed in the nasopharyngeal and oropharyngeal regions of the upper airway. Three-dimensional evaluation of the upper airway by acoustic rhinometry revealed only an increase in the volumes of the left nasal cavity after decongestant administration. A statistically significant increase in acoustic rhinometric measurements in nasal valves. When the correlation of the cephalometric findings of the nasopharyngeal region with the acoustic rhinometry findings was examined, no statistically significant relationship was found. As a result of this study, we observed an increase in the cephalometric measurements of the nasopharyngeal and oropharyngeal areas. A significant increase was observed in the minimal cross-sectional area measured by acoustic rhinometry.

Investigation of bone remodeling in gingival crevicular fluid in patients treated with rapid maxillary expansion during pubertal period

Purpose: We aimed to evaluate bone remodeling following 3-month and 6-month retention periods of rapid maxillary expansion (RME) in gingival crevicular fluid (GCF). Materials and Methods: 23 pubertal participants (15 girls- 8 boys, 12-15 years) with maxillary transversal deficiency were enrolled in the study. Following banded-type RME appliance was introduced into the mouth, RME protocol was initiated by turning the Hyrax screw twice daily (morning/evening) with ¼ activation. GCF samples were taken from right maxillary first molars at four different time points (T0: before the appliance was deployed, T1: following active phase, T2: at the end of the 3-month retention period, T3: at the end of the 6-month retention period) using paper strips. Probing depth, gingival index, plaque index, and bleeding percentage at probing were recorded. BALP, OPG, RANKL, and TNF-α levels were measured in GCF samples using ELISA kits. Results: Our study revealed that GCF's BALP and OPG levels remained unchanged over time in tension and pressure regions, and there were no statistically significant differences among regions at each time point (p>0.05). RANKL level was statistically significantly increased in the buccal region (the pressure region) at time T1 (p=0.042). The palatinal region's TNF-α level was statistically significantly higher than the buccal region at T0, T2, and T3 time points (p=0.005, p=0.042, and p=0.006, respectively). Our study showed no correlation between 3-month and 6-month retention periods and biomarkers indicating RME's bone metabolic activities. Conclusions: Further studies with different retention periods and larger sample sizes are suggested.

Rapid maxillary expansion appliance in correction of unilateral skeletal crossbite in an adult female patient: A case review

Rapid maxillary expansion appliance in correction of unilateral skeletal crossbite in an adult female patient: A case review

Effects of rapid maxillary expansion on upper airway parameters in OSA children with maxillary restriction: A CBCT study.

Rapid maxillary expansion (RME) has been proposed as an effective treatment for pediatric obstructive sleep apnea (OSA) and maxillary restriction in children. This study aimed to evaluate the effect of RME appliances on the nasomaxillary complex dimensions in children with OSA and maxillary constriction. This prospective longitudinal study included 34 children aged 8-12 years with maxillary restriction and OSA confirmed by polysomnography who had completed RME therapy. The nasomaxillary complex is segmented into the nasal cavity, maxillary sinuses, and nasopharynx. The effect of RME on nasomaxillary complex dimensions was assessed pre and posttreatment using cone-beam computed tomography, analysis, while a second standard overnight polysomnography (PSG) was performed to assess changes in respiratory parameters. Significant improvements were observed, including inferior maxillary dislocation (S-S1 distance and N-ANS), increased anterior and posterior facial height, and a 5.43 events/h reduction in Apnea-Hypopnea Index (p < .001). The nasal cavity volume increased by 2439 (±584) mm3 (p < .001), nasopharynx size increased by 883 (±479) mm3 (p = .008), mid cross-sectional area increased by 31.74 (±14.50) mm2 (p < .001), and the distance between the right and left maxillary sinuses increased by 8.37 (±3.67) mm (p < .001) all exhibited positive changes, with some insignificant variations in volume change (p = .254). RME treatment was found to be effective in improving nasal cavity and nasopharyngeal dimensions, leading to improved respiratory parameters in children with OSA and maxillary constriction. While these results are promising, considerations about the potential long-term benefits of RME on future growth are important. The study provides valuable insights into the efficacy of RME as a treatment option for this pediatric population.

Early Orthodontic Intervention in Cleft Lip-Palate and Noncleft Children with Developing Class III Malocclusion: A Clinical Study.

Orthopedic correction of skeletal class III malocclusion in a growing patient is crucial as it can circumvent future surgical procedures. The aim of the study is to evaluate the dental and skeletal effects of early orthodontic intervention of developing class III malocclusion. A final sample of 38 children in the age-group of 6-14 years having skeletal class III malocclusion was selected. Subjects were divided into two groups; group I-included 18 children (male-10, female-8) with surgically repaired cleft lip and palate and group II-20 children (male-14, female-6) without any cleft lip and palate. Cemented rapid maxillary expansion (RME) appliances with 11 mm hyrax screws were used in all patients. Elastic traction forces were applied to the reverse-pull headgear worn by the patients. Both pre- and posttreatment records along with lateral cephalograms were taken. The pre- and posttreatment mean and standard deviation measurements of the angular and linear observations were statistically analyzed with Statistical Package for the Social Sciences (SPSS) software (version 13) and were correlated through independent t-test and paired t-test. Following headgear therapy, improvement was greater in the cleft group than noncleft group with greater advancement of maxilla along with clockwise rotation of mandible in clefts. Protraction mechanics with expansion can be employed successfully in repaired cleft lip and palate and noncleft prepubertal children having developing class III malocclusion, showing concave profile, and retrusive maxilla. Accurate diagnosis and understanding of the individual growth pattern are crucial in the early interception of a class III malocclusion to achieve a more favorable facial profile. Sahoo SS, Dash JK, Sahoo PK, et al. Early Orthodontic Intervention in Cleft Lip-Palate and Noncleft Children with Developing Class III Malocclusion: A Clinical Study. Int J Clin Pediatr Dent 2023;16(5):716-723.

3D occlusal changes of upper first molars after rapid maxillary expansion on permanent versus deciduous teeth: a retrospective multicenter CBCT study

BackgroundThe purpose of this study was to compare the three-dimensional dental changes for the maxillary first molars and the overall skeletal effects achieved after expansion between the rapid maxillary expansion (RME) appliance attached to two different anchor units, the maxillary deciduous molars and the maxillary permanent first molars.MethodsPatients were retrospectively selected according to the anchorage unit used for RME: deciduous upper second molars (RME-E group; 10 M, 10 F; mean age 8.4 ± 1.1 years) and first upper permanent molars (RME-6 group; 10 M, 10 F; mean age 12.6 ± 1.8 years). CBCT scans were obtained before treatment start (T1) and after retention and removal of the expander (T2). Images were analyzed using a new three-dimensional intra-hemi-maxillary reference system. 3D landmarks were marked to calculate all changes on maxillary first permanent molars; mesio-distal and buccal-lingual inclination and rotation, as well as intermolar and interforaminal distances were calculated. The Wilcoxon test was used to compare within-group changes, whereas the Mann–Whitney test was used to compare between-group differences, with the significance level set at 0.05.ResultsIn the RME-E group, significant distorotation and lingual inclination of the first permanent molars at T2 were observed (p < 0.01); in the RME-6 group, only the buccolingual inclination of the crossbite side after RME was resulted statistically significant (p < 0.01). In both groups, intermolar and interforaminal values increased significantly (p < 0.01). Intergroup analysis showed a significantly higher distorotation and reduced buccal inclination of maxillary first permanent molars in the RME-E group after RME (p < 0.01).ConclusionsRME is effective in treating maxillary transverse hypoplasia; RME anchored too deciduous teeth spontaneously reduces buccal inclination and increases distorotation of maxillary first permanent molars, whereas anchorage to permanent molars is associated with increased buccal inclination, albeit with little clinical significance.

Evaluation of dental and skeletal effects of the asymmetric rapid maxillary expansion appliance: A three-dimensional finite element study.

Transverse maxillary deficiency is one of the most common skeletal anomalies. The incidence of posterior crossbite caused by maxillary deficiency is between 2.7% and 23.3%. Unilateral posterior crossbite is more common than bilateral crossbite. The most common treatment for skeletal posterior crossbite is rapid maxillary expansion (RME), in which the base of the maxillary bone is expanded by separating the midpalatal suture. This study compares the biomechanical effects of three different RME appliances, especially the effects on the midline, and evaluates the usability of the modified asymmetric RME (ARME) appliance for treating unilateral crossbites. Three scenarios were created with skull models using three different appliances: (1) conventional-bonded RME appliance; (2) full-cap splint RME appliance, with all teeth covered with acrylic; and (3) ARME, with all teeth on the right side and premolars and molars on the left side covered with acrylic. The finite element method was used to assess stress levels and displacements in all models after applying a 5-mm horizontal displacement to the RME screw. The lateral transverse movement of the first molars was greater with the conventional RME appliance than with the full-cap splint RME appliance. The lateral transverse movement of the first molar was greater on the left than on the right side with the ARME. The lateral transverse movement of the central incisors was greater with the full-cap splint RME appliance than with the conventional RME appliance. The lateral transverse movement of the central incisor was greater on the right than on the left side with the ARME. Asymmetrical RME appliance increases unilateral expansion compared to other appliances. Therefore, it should be used in cases of unilateral posterior crossbite. This appliance can also successfully treat posterior crossbite with upper midline deviation, since it corrects the shifted midline.

Evaluation and comparison of stresses and displacements generated by four different types of asymmetric maxillary expansion appliances in true unilateral crossbite using finite element method

True unilateral posterior crossbite can be efficiently treated by using asymmetric expansion appliances that essentially exert unilateral expansion forces thereby minimizing iatrogenic overexpansion of the normal pretreatment side. To evaluate and compare the stresses and displacements generated by four different types of asymmetric maxillary expansion appliances in true unilateral crossbite using the finite element method. A CBCT image of the skull was obtained from a 12-year-old female patient with a true unilateral posterior crossbite on the right side, for the FEM study. Asymmetrically split acrylic plate with jackscrew (ASAPJ), NORD crossbite expander, Asymmetric Maxillary Expansion appliance (AMEX), Asymmetrical Rapid Maxillary Expansion (ARME) appliances were simulated with a given force specific to the appliance. Von Mises stresses, displacements in the x, y, z-axis, and changes in the axial inclination were evaluated and compared on the selected skeletal and dental landmarks. Overall ARME seemed to generate the highest asymmetric von Misses stress on skeletal landmarks followed by NORD; ASAPJ and lowest by the AMEX. ARME also produced the highest asymmetric expansion followed by AMEX; NORD and lowest with the ASAPJ. NORD produced the minimum extrusion and buccal tipping of the canine and 1st molar followed by ASAPJ; AMEX and maximum by the ARME. Each of the four appliances expanded the maxillary arch more on the crossbite side as compared to the non-crossbite side, but the pattern of stress distribution, displacement and change in the axial inclination were unique for each appliance.

Polygraphic evaluation of the effects of different rapid maxillary expansion appliances on sleep quality: A randomized clinical trial.

The purpose of this clinical study was to assess the effects of different rapid maxillary expansion appliances on the severity of obstructive sleep apnea (OSA). Patients having a narrow maxilla and identified with OSA were divided randomly into three groups: tooth tissue-borne, tooth-borne, and bone-borne expanders. Changes in sleep parameters at baseline and 3-month follow-up detected by polygraphy were the primary outcome. Treatment of the crossbite was the secondary outcome. Dunn-Bonferroni tests, Kruskal-Wallis, and Wilcoxon analysis were applied for intra- and inter-group differences at p < 0.05 significance level. Among 46 patients randomized, apnea-hypopnea index (AHI) changed from baseline to follow-up in all groups (- 1.6, p = 0.280; 0.6, p = 0.691; - 0.45, p = 0.796, respectively), with no between-group difference (p = 0.631). Oxygen desaturation index (ODI) altered from baseline to follow-up in all groups (0.80, p = 0.977; 0.20, p = 0.932; and - 1.00, p = 0.379, respectively), with no between-group difference (p = 0.858). There was no significant difference in minimum oxygen saturation from baseline to follow-up in all groups (0.00, p = 0.401; - 2.00, p = 0.887; 0.50, p = 0.407, respectively). No significant changes were observed in supine AHI from baseline to follow-up in all groups (0.00, p = 0.581; - 1.00, p = 0.393; 0.00, p = 0.972, respectively). The upper intermolar width increased from baseline to follow-up in all groups (5.04, p = 0.000; 3.15, p = 0.001; 5.41, p = 0.00, respectively) with no between-group difference (p = 0.560). Maxillary width increased from baseline to follow-up in all groups (4.25, p = 0.001; 4.74, p = 0.00; 4.49, p = 0.001, respectively) with no inter-group difference (p = 0.963). The amount of skeletal and dental expansion obtained in the maxilla was similar in all groups. Rapid maxillary expansion was not found to be effective in OSA treatment. ClinicalTrials.gov Identifier: NCT04604392.

Does Maxillary Expansion Lead to Root Resorption?-A Comprehensive Review

The objective of this review article is to assess root resorption of conventional rapid maxillary expansion (RME) and mini screw assisted rapid palatal expansion (MARPE) with 2D and 3D radiographic imaging method. For this review article, the current literature was searched on the studies conducted on the effects of such expansion appliances on root resorption. Orthodontic patients with transverse maxillary defieiceny undergo maxillary expansion therapy for the correction of posterior crossbite. The evalution of root resorption in such patients can be done with either 2D radiographs such as perioapical radiograph, panoramic radiograph or 3D radiographs such as cone beam computed tomography. This review article will discuss the studies showing that conventional RME appliances can result in root resorption of molar teeth after the expansion procedure. In contrast, MARPE appliances have not shown significant root resorption after expansion procedures.

Evaluation of the effects of different rapid maxillary expansion appliances on airway by acoustic rhinometry: A randomized clinical trial

ObjectiveThe purpose of this 3-arm parallel trial was to compare the effects of tooth tissue-borne (TTB), tooth-borne (TB) and bone-borne (BB) rapid maxillary expansion (RME) appliances on nasal airway with acoustic rhinometry (AR). Setting and sample populationForty-six 12- to 14-year-old patients with narrow maxilla were randomly allocated into 3 study groups accordingly the type of expander: TTB, TB and BB. The participants were recruited from the Department of Orthodontics, Izmir Katip Celebi University. Materials and methodsAll patients had RME with an initial activation of two-quarter turns a day (0.5 mm) for an average of 8 days followed by 1 quarter turns per day for an average of 10 days. Disguised group allocation using opaque sealed envelopes was made with a computer-generated randomization program. The primary outcome was changes on the minimal nasal cross-sectional area (MCA). Secondary outcome included the assessment of nasal cavity volume. AR measurements were obtained at baseline (T0), immediately after the expansion (T1), and at 3 months-follow-up (T2). One-way analysis of variance (ANOVA) and Bonferroni test were used for inter-group comparison and two-way ANOVA was used for intra-group evaluation. ResultsThere were significant increases in MCA 1, 2 and nasal Vol in all groups after the treatment (95% [CI], P < 0.05) whereas in inter-group comparisons; MCA 1, 2 and nasal Vol, the changes were found to be similar (95% [CI], P > 0.05). HarmsNo serious harm was observed except for mild gingivitis due to plaque accumulation. ConclusionsRME treatment increased minimal nasal cross-sectional areas and nasal volume irrespective of appliance design. Trial registrationThis trial was registered at Clinicaltrials.gov (Identifier NCT04529057). ProtocolThe protocol was not published. FundingThis trial was financed by Izmir Katip Celebi University, Scientific Research Projects Unit [grant number 2016-TDR-SABE-0024].

Comparative Evaluation of the Stress Distribution and Transverse Displacement of the Circummaxillary Sutural System by Four Different Designs of Rapid Maxillary Expansion Appliances Using 3D Finite Element model: A Study Protocol

Background: In adolescent patient’s Rapid maxillary skeletal expansion (RME) is used with predictable clinical results for correcting transverse maxillary skeletal contraction. During RME, heavy force is directed towards the maxillary skeletal base. These forces also have effect on the palatal bone, adjacent skeletal structures and dentition. Tooth supported RME apply significant pressure on the teeth leading to varying amount of buccal inclination of premolars and molars and dental expansion. Implant assisted expanders take skeletal anchorage thus minimizing or negating the effect of heavy pressure on the teeth and supporting structures. Finite Element Analysis is a form of computer simulation. It is a non-invasive, precise method for obtaining quantitative and comprehensive knowledge about the physiological responses that occur in tissues. It outperforms other experimental methods because it creates a three-dimensional model that allows for simulation and analysis of orthodontic force systems in all three dimensions.&#x0D; Objective: The present study intends to make an assessment of four different RME designs (Banded HYRAX, Banded MARPE, MSE expander, Orthoeasy PAL expander) in terms of distribution of stress in the circummaxillary Sutural system and resulting displacement of the bones in the craniofacial complex upon activation of the respective appliance.&#x0D; Methodology: CBCT scan data of an adolescent patient will be taken from archives of a reputed scan centre. 3D skull model will be generated using CBCT data and .stl/ DICOM format will be converted into Finite Element model. The different types of RME appliances will be designed over the FE model. The expanders will be activated and the stresses generated at the sites of interest would be studied.&#x0D; Results: The study is expected to permit a clinician to select the design of RME appliances, which will produce suitable stress and displacement that will help to increase transverse width of maxilla to correct the underlying skeletal discrepancy.&#x0D; Conclusion: This study will help to arrive at a conclusion about which designs of RME will best suit clinical application of mechanics for orthopaedic expansion in a particular case.

Does mini-implant-supported rapid maxillary expansion cause less root resorption than traditional approaches? A micro-computed tomography study.

ObjectiveThis study aimed to evaluate the volume, amount, and localization of root resorption in the maxillary first premolars using micro-computed tomography (micro-CT) after expansion with four different rapid maxillary expansion (RME) appliances.MethodsIn total, 20 patients who required RME and extraction of the maxillary first premolars were recruited for this study. The patients were divided into four groups according to the appliance used mini-implant-supported hybrid RME appliance, hyrax RME appliance, acrylic-bonded RME appliance, and full-coverage RME appliance. The same activation protocol (one activation daily) was implemented in all groups. For each group, the left and right maxillary first premolars were scanned using micro-CT, and each root were divided into six regions. Resorption craters in the six regions were analyzed using special CTAn software for direct volumetric measurements. Data were statistically analyzed using Kruskal–Wallis one-way analysis of variance and Mann–Whitney U test with Bonferroni adjustment.ResultsThe hybrid expansion appliance resulted in the lowest volume of root resorption and the smallest number of craters (p < 0.001). In terms of overall root resorption, no significant difference was found among the other groups (p > 0.05). Resorption was greater on the buccal surface than on the lingual surface in all groups except the hybrid appliance group (p < 0.05).ConclusionsThe findings of this study suggest that all expansion appliances cause root resorption, with resorption craters generally concentrated on the buccal surface. However, the mini-implant-supported hybrid RME appliance causes lesser root resorption than do other conventional appliances.

Tooth-borne versus tooth-bone-borne rapid maxillary expanders according to a stereophotogrammetric evaluation of facial soft tissues: A randomized clinical trial.

To evaluate the effects of tooth-borne and tooth-bone-borne rapid maxillary expansion (RME) on soft tissue with stereophotogrammetry. Thirty two patients (15 males and 17 females) who met inclusion criteria were divided into two groups. In the first group, tooth-borne RME appliance (hyrax) was applied to 16 patients (9 males and 7 females mean age 13.4±1.3years), and in the second group, tooth-bone-borne RME appliance (hybrid hyrax) was applied to 16 patients (6 males and 10 females, mean age 13.05±1.24years). Changes in soft tissues before RME (T0) and post-retention (T1) period were evaluated by stereophotogrammetry. Linear and angular measurements were performed. Independent- and dependent-sample t tests were used to compare intra- and inter-group differences at P<.05 significance level. The data revealed statistically significant changes in nasal width, mid-face width, upper lip vermillion length/lower lip vermillion length ratio and upper lip angle in hyrax group. (P<.05) Also nasal width, lower lip length, lower lip vermillion length, anterior face height, lower face height, convexity angle and mandibular angle showed statistically significant changes in hybrid hyrax group. (P<.05) In the inter-group evaluation, no significant differences were found except upper lip and mandible angle. (P<.05). Both hyrax and hybrid hyrax expanders had effects on soft tissue profile. Anterior face height and lower face height increased in both groups. Upper lip length increased by 0.36mm in the hybrid group and 0.10mm in the hyrax group. This trial was registered at Clinicaltrials.gov (Identifier: NCT04828213).

Investment casting with FFF (fused filament fabrication)-printed appliances: the intermediate step.

Some modifications of orthodontic appliances such as the rapid maxillary expansion (RME) device with a Hyrax screw or Herbst are fabricated using traditional investment casting (lost-wax casting). This is precise but very labor-intensive. New technologies enable us today to use direct selective laser sintering (SLS) to produce freeform metallic structures. These machines are very expensive and only available in specialized laboratories. The aim of this investigation was to combine fused filament fabrication (FFF) 3D printing with wax-based filaments to produce orthodontic appliances via investment casting. For demonstration purposes, a lingual arch, a palatal arch, and an RME appliance were digitally designed based on an intraoral scan. The *.stl files were sliced and printed with a dual-nozzle FFF printer. The object was printed with a wax-based filament especially suited for investment casting, and support structures were printed with water-soluble polyvinyl-alcohol (PVA) filament. The printed objects were cast in metal and finished. All appliances were successfully cast and polished. They were provisionally placed intraorally. The fit was clinically very good and comparable to traditionally crafted appliances. The printing and handling of the parts made of these special filaments is challenging. With this experiment, the successful production of investment casting using FFF printing was shown for the first time.

A postero-anterior cephalometric evaluation of different rapid maxillary expansion appliances

The purpose of the study was to evaluate dental and skeletal changes induced by tooth-bone-borne, tooth-tissue-borne, and tooth-borne rapid maxillary expansion (RME) appliances using postero-anterior (PA) cephalometric radiographs. A total of 54 patients' (25 boys, 29 girls) PA cephalometric radiographs who had bilateral posterior crossbite and RME treatment were included and divided into three groups according to the type of appliance used during treatment: tooth-bone-borne RME appliance (hybrid Hyrax) (7 boys, 11 girls, mean age 13.28 ± 1.20 years), tooth-tissue-borne RME appliance (TTB) (8 boys, 10 girls, mean age 13.08 ± 1.06 years) and tooth-borne RME appliance (Hyrax) (10 boys, 8 girls, mean age 12.05 ± 1.35 years). Pretreatment (T0) and posttreatment (T1) PA cephalometric radiographs were analyzed with Dolphin software v. 11.7 (Chatsworth, CA). The comparisons of the groups were performed with Two-way analysis of variance. P < 0.05 was considered statistically significant. Significant and equal increase of right molar relationship and upper intermolar molar widths occurred in all groups. Dental midline discrepancy showed significant increase in only hybrid Hyrax group between T0 and T1. Significant increases were reported for lateronasal width in hybrid Hyrax and tooth-tissue-borne groups (P < 0.05). Both skeletal and dental changes were observed after RME in all groups. However, the greatest skeletal changes were seen in hybrid Hyrax and tooth-tissue-borne groups.

Comparison of skeletal and dentoalveolar changes between pure bone-borne and hybrid tooth-borne and bone-borne maxillary rapid palatal expanders using cone-beam computed tomography

Objectives: The objectives of the study were to compare the skeletal, dentoalveolar, and periodontal changes between two types of microimplant-assisted rapid maxillary expansion appliances: The bone-anchored maxillary expanders (BAME) and the tooth-bone-anchored maxillary skeletal expander (MSE). Materials and Methods: Thirty-four patients with a transverse maxillary deficiency were divided into two groups; the first group (16 patients, average age 14.9 years) was treated with the MSE appliance, and the second group (18 patients, average age 13.8 years) was treated with the BAME appliance. Cone-beam computed tomography scans were taken at pre-treatment (T1) and immediately post-expansion (T2) to measure the changes in midpalatal suture opening, total expansion (TE), alveolar bone bending, dental tipping (DT), and buccal bone thickness. Data were analyzed using paired t-test and two-sample t-test. Results: Midpalatal suture separation was found in 100% of the patients in both groups. The TE at the first molar was 5.9 mm in the MSE group and 4.7 mm in the BAME group. The skeletal contributions were 56% and 83% of TE for the MSE and BAME groups, respectively. Significantly less dental buccal tipping and buccal bone loss were found with the BAME group. The midpalatal suture in both groups exhibited a parallel opening pattern in the axial plane. Conclusion: The use of BAME appliance resulted in greater skeletal effects, less dental tipping, and less buccal bone reduction compared to MSE appliance (immediately after maxillary expansion).

Evaluation and Comparison of Root Resorption Resulting from Traditional and Bone-borne Rapid Maxillary Expansion Appliances Using Cone-beam Computed Tomography

Evaluation and Comparison of Root Resorption Resulting from Traditional and Bone-borne Rapid Maxillary Expansion Appliances Using Cone-beam Computed Tomography

Evaluation of Initial Stress Distribution and Displacement Pattern of Craniofacial Structures with 3 Different Rapid Maxillary Expansion Appliance Models: A 3-dimensional Finite Element Analysis.

This study aimed to describe the displacement of anatomical structures and the stress distributions caused by the Hyrax, fan-type, and double-hinged expansion screws via the 3-dimensional (3D) finite element method (FEM). The 3D FEM was based on the computed tomography data of a 12-year-old patient with a constricted maxilla. The Hyrax model included 1,800,981 tetrahedral elements with 2,758,217 nodes. The fan-type model included 1,787,558 tetrahedral elements with 2,737,358 nodes. The double-hinged model included 1,777,080 tetrahedral elements with 2,722,771 nodes. The von Mises stress distributions after 0.2 mm of expansion and displacement patterns after 5 mm of expansion were evaluated. The highest stress accumulation was observed in the sutura zygomatico maxillaris area with all 3 appliances. An increase in stress was noted at the pterygomaxillary fissure, the medial and lateral pterygoid process of the sphenoid bone, and the nasal areas. The wedge-shaped skeletal opening was observed with all 3 appliances. In the transverse plane, maximum posterior expansion was achieved with the Hyrax appliance, whereas the maximum anterior expansion was observed with the double-hinged appliance. The maxilla moved inferiorly and anteriorly with all the 3 appliances. The greatest inferior displacement of the maxilla was recorded with the Hyrax appliance, whereas anterior maxillary displacement was the greatest with the double-hinged appliance. All the appliances showed similar stress distributions. The use of double-hinged screw caused a slight anterior displacement of point A. The fan-type and double-hinged appliances were shown to be more effective on anterior maxillary constriction, whereas the Hyrax appliance might be chosen for resolving maxillary posterior constriction.

Age-related changes in the effect of rapid maxillary expansion on the position of labially impacted maxillary canines: A case-control study

The early diagnosis and interception of potential maxillary canine impaction is the most desirable approach for correcting their path of eruption. However, there is still a lack of evidence regarding the effect of rapid maxillary expansion (RME) on labially impacted canines. This study aimed to investigate the age-related effect of RME on labially impacted maxillary canines in order to reduce the risk of their impaction in the mixed dentition and to examine the proper timing of interceptive treatment. All patients aged 7-10years were treated with an RME appliance using the same protocol. The distance to the occlusal plane, axis to the midline, and distribution in different sectors-depending on the patients' age-were evaluated for maxillary canines before and after treatment on panoramic radiographs in order to detect changes in the position of the impacted canines. These geometric measurements in the impacted canines were also validated by observing the nontreated canines at each age. Significant differences existed between the impacted canines and the erupted canines in all 3 categories in all age groups. RME treatment modulated the position of the impacted canines in all age groups. Interestingly, a statistically significant difference before and after RME in all categories was detected in patients aged<8years. A discriminant analysis also showed a positive association of RME treatment with the risk of labially impacted canines. The standardized regression coefficients showed that the angulation of the maxillary canine was the most important predictor for impaction. Our findings indicate that RME treatment in the early mixed dentition was effective for managing labially impacted maxillary canines. An age of 7-8years with early mixed dentition might be the most appropriate timing for therapeutic intervention on the basis of RME treatment for buccal canine impaction.